DroidFS allows you to create encrypted virtual volumes on which you can safely store and access files. Currently, DroidFS supports only gocryptfs. This algorithm protects file contents and file names but doesn't hide directory structure or file sizes. If you want more details, take a look on their github repository. DroidFS is free, open-source, and you can find the project's repository on github or on the gitea instance of the Chapril project. Warning ! Security is relative. DroidFS does not come with any warranty and should not be considered as an absolute safe way to store files.